[Image-guided radiotherapy by in-room CT-linear accelerator combination].

Area of Science:

• Radiation oncology
• Medical imaging
• Radiotherapy technology

Context:

• Intensity-modulated radiation therapy (IMRT) requires precise target localization due to reduced margins and steep dose gradients.
• The "CT on rails-LINAC" system provides in-room CT imaging immediately before treatment.
• This enables quantification of anatomical variations and real-time tumor position verification.

Purpose:

• To evaluate the utility of an in-room CT on rails-LINAC system for image-guided radiotherapy.
• To assess the potential for improving target localization and treatment accuracy in IMRT.
• To identify challenges and opportunities for clinical integration of CT-guided radiotherapy.

Summary:

• The CT on rails-LINAC system facilitates pre-treatment CT imaging in the treatment position, allowing for assessment of inter- and intra-fractional variations.
• Tumor position can be verified and corrected, and re-planning is feasible if tumor shape changes.
• While clinical experience is limited and integration challenges exist (software, imaging frequency, cost), the technology shows promise.

Impact:

• CT-image-guided radiotherapy offers enhanced precision for treating tumors, particularly in the prostate, brain, and spine.
• Potential to minimize radiation exposure to healthy tissues by improving accuracy.
• Facilitates adaptive radiotherapy strategies, improving treatment efficacy and patient safety.